Some distributed electric power supply systems have been proposed in which a plurality of electric power generation facilities are connected to demand loads via a power transmission grid network such that operation control of each of the electric power generation facilities can be performed.
Proposed examples of distributed power supply systems include Patent Literatures 1 to 3.
A distributed electric power supply system disclosed in Patent Literature 1 has a plurality of electric power generating apparatuses that supply electric power to power loads and an electric power generation number controller operable to control the number of the electric power generating apparatuses which are operating. The plurality of electric power generating apparatuses and the electric power generation number controller are connected via a communication network. When a plurality of electric power generating apparatuses give a whole amount of power loads in the system in a distributed manner, the electric power generation number controller determines the number of operating or active electric power generating apparatuses all of which generate the amount of electric power equal to or greater than thresholds by removing a small amount and insufficient electric power generation.
A distributed electric power supply system disclosed in Patent Literature 2 determines active or operating electric power generators so that minimize power transmission loss (suppress power flow) in order to consider inefficiency resulting from power transmission loss in a power transmission network.
A distributed electric power supply system disclosed in Patent Literature 3 performs control for separating certain power loads (power loads of less priority) when a commercial power supply is interrupted and a distributed electric power supply cannot cover the total amount of electric power required. Furthermore, this system receives an input of a power cut period from an administrator and predicts and calculates an electric power demand for that period (power cut period) with an electric power demand prediction tool, thereby verifying the sufficiency of the demand.
Additionally, while smart grids for a commercial power supply are being developed, other systems are also being developed to construct and operate relatively small power transmission grids within a predetermined area independently of the infrastructural network (commercial power supply network). The grids operated in the predetermined area are referred to as microgrids, picogrids, or cells. The predetermined area is set in an appropriate manner at each necessary time. For example, the predetermined area is formed by a regional area, a city, a building, several houses, or the like. Furthermore, a grid network for a plurality of buildings such as a school or a hospital is also being developed.